WO2022002903A1

WO2022002903A1 - Device for ejecting a mould, comprising a chain with sliding links and an adjustment shim

Info

Publication number: WO2022002903A1
Application number: PCT/EP2021/067792
Authority: WO
Inventors: Sylvain BELLIARD
Original assignee: Faurecia Interieur Industrie
Priority date: 2020-06-29
Filing date: 2021-06-29
Publication date: 2022-01-06
Also published as: US20230321876A1; EP4171916A1; FR3111838B1; CN115734861A; FR3111838A1

Abstract

The ejection device comprises: - a thrust device (14) translatably movable along a first axis (A1), - an ejection member (28) translatably movable along a second axis (A2) different from the first axis (A1), - a transfer device (26) which connects the thrust device (14) and the ejection member (28), and comprises a drive chain (40) comprising at least two drive links (42) translatably movable in a sliding direction. The ejection device further comprises an adjustment shim (50) mounted on the thrust device (14), the adjustment shim (50) comprising an adjustment surface (64) forming an adjustment angle (σ), the drive chain (40) being mounted on the adjustment surface (64).

Description

DESCRIPTION

TITLE: Mold ejection device comprising a chain of sliding links and an adjusting wedge

The present invention relates to an ejection device for a mold for producing a molded article in a mold cavity intended to allow the ejection of the molded article out of the mold cavity, said device comprising:

- a thrust device movable in translation along a first axis between a retracted position and an ejection position,

- at least one ejection element movable in translation along a second axis, different from the first axis, between a retracted position and an ejection position,

- at least one transfer device connecting the pushing device and the ejection element, said transfer device being arranged to move the ejection element along the second axis between its retracted position and its ejection position when the pushing device is moved along the first axis between its retracted position and its ejection position, the transfer device comprising a transmission chain comprising at least two transmission links movable in translation in a sliding direction with respect to the other and relative to the pushing device and the ejection element. Such an ejection device makes it possible, for example, to unmold a molded article of complex shape, for example a non-planar part or having zones extending in one or more planes different from a plane perpendicular to the ejection direction or comprising elements projecting in a direction different from the ejection direction or else undercut areas. Indeed, by providing for example an ejection device comprising an ejection rod ejecting the part along the first axis and another rod forming the ejection element and ejecting the part along the second axis, a part of complex shape can be ejected.

Document EP-3 210 735 describes such an ejection device, in which provision is made to slide the links of the transmission chain along sliding surfaces forming an angle with respect to a direction perpendicular to the first axis of movement of the chain of transmission. The angle is chosen to synchronize the movement of the ejection element with respect to that of the pushing device, in particular to accelerate or to slow down the movement of the ejection element with respect to to that of the pushing device. Such synchronization makes it possible to adjust the movement of the ejection element relative to one or more other ejection rods also moved by the pushing device to demold other parts of the molded article so that the element ejector and ejector rods reach their ejection position at the same time while the travel paths of the ejector member and other ejector rods between the retracted position and the ejection position are different .

However, this document does not describe a simple way to adjust this angle so that it can be easily changed when the timing of the displacement of the ejector member relative to that of the pushing device needs to be changed.

One of the aims of the invention is to overcome this drawback by providing an ejection device which makes it possible to simply modify the angle at which the links slide relative to each other.

To this end, the invention relates to an ejection device of the aforementioned type, further comprising at least one adjustment wedge mounted on the thrust device, said adjustment wedge comprising an adjustment surface forming an adjustment angle with respect to a direction substantially perpendicular to the first axis, the transmission chain being mounted on said adjustment surface so that the sliding direction is substantially parallel to said adjustment surface.

Thus, the adjustment shim makes it easy to adjust the sliding angle of the transmission links relative to each other by choosing the adjustment angle of the adjustment surface on which the transmission chain is slidably mounted. When the sliding angle has to be changed, it suffices to provide another adjustment shim having an adjustment surface forming the desired angle and to mount this new wedge on the pushing device. Thus, the sliding angle can be changed simply without requiring, in particular, to modify the pushing device itself.

According to other optional characteristics of the ejection device, taken individually or in any technically conceivable combination:

- the adjustment angle is negative to delay the movement of the ejection element relative to the pushing device, positive to accelerate the displacement of the ejection element relative to the pushing device or zero to move the ejection element at the same speed as the pushing device;

- the transmission chain comprises a connecting link, mounted movable in translation on a transmission link on the one hand, the ejection element being mounted movable in rotation on said connecting link about an axis of rotation substantially perpendicular to the first and second axes;

- the connecting link comprises two displacement surfaces of the ejection element, the two displacement surfaces each extending from a central part of the connecting link towards an edge of said connecting link, the connecting link s' orienting relative to the ejection element, the travel surfaces allowing this orientation as a function of the adjustment angle when the ejection element moves along the second axis between its retracted position and its ejection position;

- the two travel surfaces of the connecting link are substantially symmetrical to each other with respect to the central part of the connecting link;

- the connecting link is linked to the ejection element by a connecting element articulated to the connecting link and to the ejection element so as to allow rotation of the connecting link relative to the element d ejection;

- the transmission chain comprises an adjustment link mounted movable in translation on a transmission link, the adjustment link comprising a positioning surface extending on the adjustment surface of the adjustment shim so that the sliding direction between the adjustment link and the transmission link is substantially parallel to said adjustment surface;

- Each link of the transmission chain comprises at least two sliding surfaces, arranged to slide on sliding surfaces of adjacent links, said sliding surfaces extending substantially parallel to the adjusting surface of the adjusting shim;

- Each link in the transmission chain is linked to at least one other link in the transmission chain by at least one connecting element designed to allow the links to move in translation relative to each other; and

- the transmission links are identical to each other. Other aspects and advantages of the invention will become apparent on reading the following description, given by way of example and made with reference to the accompanying drawings, in which:

[Fig 1] - Fig. 1 is a schematic perspective representation of a first mold part comprising an ejection device according to one embodiment of the invention, the ejection device being in the retracted position,

[Fig 2] - Fig. 2 is a schematic perspective view of part of the ejection device of FIG. 1, [Fig 3] - Fig. 3 is a schematic perspective representation of an adjusting wedge and an adjusting link of the ejection device of FIG. 2,

[Fig 4] - Fig. 4 is a schematic perspective representation of a connecting link and an ejection element of the ejection device of FIG. 2,

[Fig. 5] [Fig 6] [Fig 7] - Figs. 5 to 7 are schematic cross-sectional representations of the first mold part of FIG. 1, the ejection device passing from the retracted position to the ejection position via an intermediate position, and

[Fig. 8] [Fig 9] [Fig 10] [Fig 11] [Fig 12] - Figs. 8 to 12 are schematic cross-sectional representations of the first mold part, with the ejector device in the retracted position, and showing different movements of the ejector device.

With reference to FIG. 1 describes a mold for making 1 of a molded article 2 which may have any shape suitable for being molded. Such an embodiment mold 1 is, for example, an injection mold, a compression mold, a foaming mold or the like. More generally, a mold allows a desired shape to be imparted to a material disposed in a mold cavity having the desired shape of the article to be molded.

The molded article 2 is for example a part of a motor vehicle or the like. More particularly, according to the embodiment shown in the figures, the molded article 2 comprises a main surface 4 and a part 6 undercut with respect to the main surface, that is to say a part comprising at least a surface that cannot be released from the mold by simply separating two mold parts and requiring a complementary molding element which can be moved in a direction different from the direction of the separation of the two mold parts.

The embodiment mold 1 comprises a first part 8 and a second part (not shown to simplify the figures), movable relative to each other between an open position, in which the first and second parts are spaced apart from one another. on the other and a closed position, in which the first and second parts are brought together so as to define a closed main mold cavity. The main molding cavity has a shape complementary to the main surface 4 of the molded article to be produced. The movement from the closed position to the open position takes place in an opening direction D, shown in the figures. The first part 8 comprises a molding surface 10 defining, together with a molding surface of the second part, the main mold cavity when the first and second parts are in the closed position. The main surface 4 of the molded article 2 is such that it can be separated from the molding surface 10 by a movement of the molded article in a single ejection direction, for example parallel to the opening direction D Consequently, the main surface 4 is not necessarily planar and may have any shape allowing demoulding by displacement of the molded article 2 in the direction of ejection. Thus, according to the embodiment shown in the figures, the main surface 4 comprises a first part 5 substantially perpendicular to the opening direction D and a second part 7 inclined relative to the first part 5. It should be noted that the The main mold cavity could also be arranged to form elements projecting from the main surface 4, for example ribs, as long as these elements can also be separated from the main mold cavity by movement of the molded article 2 according to the ejection direction.

According to the embodiment shown in the figures, the main molding cavity is in fluid communication with a secondary molding cavity defined by the molding surface 10 of the first part 8 and by a complementary molding surface 12 carried by a device for molding. ejection according to the invention, as will be described later. The complementary molding cavity has a shape complementary to the undercut part 6 of the molded article 2. The main molding cavity and the secondary molding cavity together form the molding cavity of the embodiment mold 1. It is understood that several Secondary mold cavities may be provided depending on the shape of the article to be molded.

The production mold 1 is for example an injection mold arranged to inject a plastic material at a predetermined pressure into the mold cavity. To this end, the production mold 1 comprises all the means making it possible to carry out and control this injection and the formation of the part, such as one or more injection nozzles of the plastic material, means for regulating the temperature of the molding cavity, means for actuating and moving the first and second parts of the production mold 1, etc. Since such means are known, they will not be described in more detail here.

The production mold 1 comprises an ejection device arranged to facilitate the removal of the molded article 2 from the production mold after its production. Once the molded article 2 is made, the first and second mold parts are moved to the open position. The molded article 2 then lies against the molding surface of the first part 8, as shown in Figs. 1 and 5, and the ejection device is arranged to move the molded article 2 away from the molding surface 10, as shown in FIG. 7, in order to allow the gripping of the molded article 2 to take it out of the production mold. It should be noted that the ejection device can be actuated during the opening of the mold 1 so that the ejection of the molded article 2 does not necessarily start when the mold is already in the open position.

The ejection device comprises a thrust device 14 movable in translation in the first part 8 along a first axis A1 between a retracted position, shown in Figs 1 and 5, and an ejection position, shown in Fig. 7. The first axis A1 extends in the direction of ejection and is for example substantially parallel to the direction of opening D so that, in the ejection position, the molded article 2 is spaced from the molding surface. 10 in the space between the first part 8 and the second part of the mold.

The pushing device 14 comprises at least one ejection plate 16 disposed movably in translation along the first axis A1, in a space 18 of the first part 8. In the retracted position, the ejection plate 16 is arranged. in an upstream part 20 of the space 18, that is to say the part of the space 18 furthest from the molding surface 10, and, in the ejection position, the ejection plate 16 is disposed in a downstream part 22 of the space 18, that is to say the part of the space 18 closest to the molding surface 10.

The pushing device 14 further comprises an actuating element 24 integral with the movement of the ejection plate 16, the actuating element 24 is connected to a transfer device 26 which is itself connected to an ejection element. 28.

The ejection element 28 is movable in translation along a second axis A2 different from the first axis A1. According to the embodiment shown in the figures, the ejection element 28 is a movable block carrying the complementary molding surface 12. Thus, in the retracted position, the block is arranged in the first part 8 so that the surface of complementary molding 12 extends opposite the molding surface 10 of the first part 8 and defines therewith the complementary molding cavity. The movable block comprises an actuating end 30. The ejection element 28 further comprises an actuating rod 31 connected, by its downstream end, to the actuating end 30 of the movable block and extending along the second axis A2. The upstream end of the actuating rod 31 is for its part connected to the transfer device 26, as will be described later. It should be noted that the actuating rod 31 could be made in one piece with the movable block. However, providing a movable block and an actuating rod 31 formed of two separate parts makes it possible to improve the adaptability of the ejection element 28 to different molds, as will be described later.

The second axis A2 forms an angle a with the first axis A1. The value of the angle a is chosen depending on the shape of the molded article. More particularly, in the case where the molded article comprises an undercut zone 6, the angle a depends on the distance necessary to exit the movable block from the undercut zone 6 during the ejection of the molded article 2. , as will be described later.

Thus, the ejection element 28 is movable between a retracted position and an ejection position, respectively when the pushing device 14 is in the retracted position and in the ejection position by means of the transfer device 26 which is arranged to transform the movement of the pushing device 14 along the first axis A1 into movement of the ejection element 28 along the second axis A2, as will now be described.

The transfer device 26 comprises a guide element 33 extending in the first part 8 of the mold from the space 18 to the molding surface 10 along a path extending along the first axis A1 in the space 18 and along the second axis A2 in the part of the first part 8 of the mold extending between the space 18 and the molding surface 10. The guide element 33 comprises a first section 32, for example formed by two sections 34, s 'extending in the space 18 along the first axis A1 and defining, for example between the two sections 34, a first groove, or guide slide. The guide element 33 also comprises a second section 36, for example formed by a tube, extending in the first part 8 between the space 18 and the molding surface 10 along the second axis A2, and defining, for example in the internal volume of the tube, a second groove, or slide, for guiding. The guide element 33 is fixed relative to the first part 8 of the mold.

It should be noted that the ejection plate 16 is movable in translation relative to the guide element 33. For this purpose, the ejection plate 16 comprises a recess 38 arranged to receive the two profiles 34 of the first section 32. This imprint 38 is able to slide around and along the first section 32, which allows the ejection plate 16 to be moved between its retracted position and its ejection position, as will be described later.

The transfer device 26 further comprises a transmission chain 40 connected on the one hand to the pushing device 14 and on the other hand to the ejection element 28. The transmission chain 40 comprises at least two transmission links 42. linked together and movable relative to each other in translation. The translation of the transmission links 42 takes place along sliding surfaces 44, the sliding surfaces 44 being substantially parallel to one another. The transmission links 42 are also movable in translation relative to the thrust device 14 and to the ejection element 28. For this purpose, each transmission link 42 comprises at least two sliding surfaces 44, one forming one translation surface with an adjacent transmission link 42 and the other forming a translation surface with an adjacent transmission link 42 or with an adjusting link 46 or with a connecting link 48, as will be described later. The length of the sliding surfaces 44 is such that the transmission links 42 do not disengage from each other when moving the ejection device between its retracted position and its ejection position. In addition, these sliding surfaces 44 are of sufficient length to be able to transmit the thrust forces from the ejection plate 16 to the ejection element 28.

Each sliding surface 44 forms an angle b with a direction perpendicular to the first axis A1, as shown in Figs. 8 to 12. The adjustment of the angle b relative to the first axis A1 makes it possible to adjust the advance or the delay of displacement of the ejection element 28 relative to the displacement of the pushing device 14, as will be described. later.

The number of transmission links 42 of the transmission chain 40 depends on the path followed by the transmission links 42 in the guide element 33 and is arranged so that the transmission chain 40 connects the pushing device 14 to the element. ejection 28. More particularly, the transmission chain 40 connects an adjustment wedge 50 integral with the ejection plate 16 at the upstream end of the actuating rod 31. The adjustment wedge 50 will be described later.

Thus, the transmission chain 40 can comprise more than two transmission links 42, including two end transmission links connected respectively to an adjustment link 46 and to a connecting link 48, and at least one intermediate transmission link connected to the two end transmission links or several transmission links successively connected to one another so as to form the transmission chain 40 from the adjustment link 46 to the connecting link 48.

All the transmission links 42 are identical, that is to say they have an identical shape and structure, whether they are end transmission links or intermediate transmission links. Several forms of transmission link 44 can be envisaged. One of these shapes will be described below and a person skilled in the art may refer to document EP-3 210 735 to see other examples of possible shapes. Whatever form is chosen, it must be adapted so that the transmission links 42 can cooperate with each other and with the guide element 33 over the entire travel path of the transmission links 42 so that the transmission links 42 are guided in the guide element 33 over the entire travel path.

To this end, each transmission link comprises at least one guide surface 52 arranged to cooperate with the first and second guide grooves of the first and second sections 32 and 36 of the guide element 33 over the entire travel of the chain. 40. By "cooperate" is meant that the guide surface 52 is in sliding, sliding and / or rolling contact with one of the guide grooves over the entire travel path of the transmission link 42 carrying this surface of guide 52. Thus, when the transmission link 42 is located in the first section 32 of the guide element 33, the guide surface 52 is in contact with at least one surface of the first guide groove and when the guide link transmission 42 is located in the second section 36, the guide surface 52 is in contact with at least one surface of the second guide groove. According to the embodiment shown in the figures, the guide surface 52 is formed by a roller 54 having a diameter substantially equal to the width of the guide grooves. The roller 54 is for example mounted on an axis extending projecting from the transmission link 42 and fixed relative to this transmission link. The axis has for example a substantially circular section. The cylindrically shaped peripheral surface 54 forms the guide surface by being in sliding contact with the walls of one of the guide grooves at at least two points on the surface. According to one embodiment, each transmission link comprises two rollers 54 arranged to cooperate respectively with one of the profiles 34 or tube forming the first section 32 and the second section 36. According to one embodiment, the rollers 54 are furthermore movable in rotation with respect to the transmission links, so that the guide surface 52 can also roll on the walls of the guide grooves. Thus the guiding of the transmission links in the guide element 33 is effectively ensured, which avoids any risk of jamming or engagement of the ejection device by jamming of a transmission link 42 in the control element. guide 33. It should be noted that the guide surface 52 could be defined directly by the shape of the transmission link 42 without requiring the addition of a roller, this shape can be arranged to define a sliding contact with the guide element 33.

As indicated above, to ensure the translational movement of the links with respect to each other and with respect to the adjustment link 46 and with respect to the connecting link 48, each transmission link 42 comprises two sliding surfaces 44, each formed by a wall of the transmission link 42. The walls forming the sliding surfaces 44 can be arranged in different ways as long as they are complementary and allow a displacement in translation with respect to one another. According to the embodiment shown in the figures, each transmission link 42 has, in a plane perpendicular to the first axis A1 and to the second axes A2, an S-shaped section. Thus, each transmission link 42 comprises two external branches and an internal branch interconnected so as to define two grooves, each extending between the internal branch and one of the external branches and opening in two opposite directions. The opposite walls of the outer legs and of the inner leg each define a sliding surface 44. Thus, each transmission link comprises six sliding surfaces 44 defined by the walls facing each groove and by the outer surfaces of the outer legs of the link. transmission 42. Such an embodiment makes it possible to ensure a robust connection between the transmission links 42, since each transmission link 42 is held in two grooves of adjacent links, including for the end transmission links, such as this will be described later. Each sliding surface 44 extends in a sliding direction and all of the sliding surfaces 44 are parallel to each other.

According to the embodiment shown in FIG. 2, the transmission links 42 are further linked in pairs by connecting elements 56. Each connecting element 56 is articulated to two transmission links 42 so as to allow the translational movement of the two linked transmission links 42. 'one relative to the other while avoiding disengagement of the transmission links 42 from one another, in particular when the transmission chain 40 is not mounted in the production mold. In other words, the connecting element 56 is adapted to allow the sliding of the sliding surfaces 44 of two transmission links 42 on each other while avoiding the separation of the transmission links 42 when the transmission chain is. handled outside the mold, for example during its assembly and its mounting in the mold. Such a connecting element 56 is for example formed by a connecting rod comprising two opposite ends 58, which are each articulated to one of the transmission links 42 linked by the connecting element 56. More particularly, each end 58 comprises for example an opening, for example of oblong shape, receiving, movably in rotation, the circular axis carrying the roller 54 of a transmission link 42. A movement is allowed between the axis and the connecting element in order to allow the translation of the links with respect to each other. According to one embodiment, the outer surface of the ends 58 also form a guide surface 52 of the transmission links 42 in the guide element 33, as described above. According to a variant, the connecting element 56 is formed by a flexible element connected at each of its ends to one of the transmission links 40 linked by the connecting element 56. It is understood that a transmission link 42 can be linked to an adjacent transmission link 42 by a connecting element 56 and to another adjacent link by another connecting element 56 by providing projecting pins on each side of the links of the transmission chain 40. Such elements link 56 are described in document FR-3 065 388 and those skilled in the art will be able to refer to them to see other examples of possible embodiments.

As indicated previously, the transmission chain 40 comprises two end transmission links 42, one of which is linked to an adjustment link 46 and the other is linked to a link 48. More particularly, the link link. End transmission 42 closest to ejector plate 16 is linked to adjustment link 46 and end transmission link 42 closest to actuating rod 31 is linked to linkage 48.

The adjusting link 46 ensures the cooperation of the transmission chain 40 with the pushing device 14 by means of the adjusting wedge 50. As shown in FIG. 3, the adjustment link 46 has the shape of a half transmission link 40. Thus, the adjustment link 46 has on one side a half S shape formed of an outer branch 58 and an inner branch 60. defining between them a groove 62. The groove 62 allows the adjustment link 46 to be engaged with the end transmission link 42 and to be movable in translation with respect to the latter, in the same way as two links transmission 42 cooperate together. Thus, the external branch 58 is introduced into a groove of the end transmission link 42 and the groove 62 receives an external branch of this end transmission link 42. The outer branch 58 and the inner branch 60 thus define three sliding surfaces 44 a, 44b, 44c in sliding contact with three sliding surfaces 44 of the transmission link. 42 end. The adjustment link 46 may further be linked to the end transmission link 42 by a link member 56, as previously described. On the side of the internal branch 60 opposite to the groove 62, the adjustment link 46 comprises a positioning surface 45 parallel to the sliding surfaces 44a, 44b, 44c of the adjustment link 46. The positioning surface 45 is arranged to be applied. on an adjustment surface 64 of the adjustment shim 50, as will now be described.

The adjusting wedge 50 is mounted on the pushing device 14 in a reversible manner, that is to say that the adjusting wedge 50 can be removed from the pushing device 14 in order to replace it with another adjusting wedge. To this end, the adjusting wedge 50 is for example screwed onto the actuating element 24 by means of a screw 66, as shown in FIG. 2. The adjustment surface 64 is arranged to form an adjustment angle s with respect to a direction substantially perpendicular to the first axis A1 when the adjustment wedge 50 is mounted on the actuating element 24, as shown in Figs. 2 and 3. Thus, by applying the positioning surface 45 of the adjustment link 46 on the adjustment surface 64, the positioning surface 45 of the adjustment link 46 is forced to form an angle equal to the adjustment angle s. with a direction substantially perpendicular to the first axis A1. The sliding surfaces 44a, 44b, 44c of the adjustment link 45 and the sliding surfaces 44 of the transmission links 42 being parallel to the positioning surface 45 of the adjustment link 46, these sliding surfaces 44 thus form an angle equal to the adjustment angle s with a direction substantially perpendicular to the first axis A1. In other words, the angle b is equal to the adjustment angle s and the sliding direction is parallel to the adjustment surface 64. Thus, by choosing the value of the adjustment angle s, we adjust l 'angle b formed by the sliding surfaces 44 of the transmission chain 40 with respect to a direction substantially perpendicular to the first axis A1 and by changing the adjustment angle s by replacing the adjustment shim 50 with another, it is possible change the angle b. Therefore, by changing a single part of the ejection device, it is possible to modify the behavior of this ejection device during its movement between the retracted position and the ejection position in order to adapt it to the article. molded 2 to be produced, as will be described later. Changing the adjustment wedge 50 by another having a different adjustment angle is particularly simple since it suffices to unscrew the adjustment wedge 50 from the actuating element 24 and screw another one with it. the desired adjustment angle. By application of the positioning surface 45 on the adjustment surface 64, it is meant that the adjustment link 46 is secured to the adjustment wedge 50 by a connecting element 56 preventing relative movement between the adjustment link 46 and the wedge. adjustment 50, as shown in FIG. 2. For this purpose, the axis of the adjusting wedge 50 receiving one end 58 of the connecting element 56 is for example of oblong shape, substantially complementary to the oblong opening of the connecting element 56, in order to 'prevent relative displacement between the adjustment link 46 and the adjustment wedge 50. For this purpose, the adjustment wedge 50 and the adjustment link 46 comprise at least one roller 54, as previously described with reference to the transmission links 42. The rollers 54 also form guide surfaces 52, as also described above with reference to the transmission links 42.

The connecting link 48, more particularly shown in FIG. 4, connects the transmission chain 40 with the ejection element 28, and more particularly with the actuating rod 31. It is arranged in particular to allow the actuating rod 31 to adapt to the 's adjustment angel chosen. The connecting link 48 has, like the adjustment link 46, on one side a half-S shape formed of an external branch 68 and an internal branch 70 defining between them a groove 72. The groove 72 allows the link link 48 to be engaged with the end transmission link 42 and to be movable in translation with respect to the latter, in the same way that two transmission links 42 cooperate together. Thus, the outer branch 68 is introduced into a groove of the end transmission link 42 and the groove 72 receives an outer branch of this end transmission link 42. The outer branch 68 and the inner branch 70 thus define three sliding surfaces 44 e, 44f, 44g in sliding contact with three sliding surfaces 44 of the end transmission link 42. The link 48 may further be linked to the end transmission link 42 by a link 56, as described above. On the side of the internal branch 70 opposite to the groove 72, the connecting link 48 comprises two displacement surfaces 74 of the ejection element 28 extending on either side of a central part 76 of the link. link 48 and each converging towards an edge of the internal branch 70 from this central part 76. By each converging towards an edge of the internal branch 70 is meant that each travel surface 74 is inclined between the central part 76 and the corresponding edge of the internal branch 70 so that the connecting link 48 has a substantially triangular shape on the side of the internal branch 70 opposite to the groove 72. Thus, each travel surface 74 forms an angle Q with the sliding surface 44e formed by the internal branch 70, the travel surfaces 74 forming two sides of a triangle, the third side of which is formed by the sliding surface 44e. The angle formed by one of the travel surfaces 74 is equal to the angle formed by the other travel surface 74 so that the two travel surfaces 74 are substantially symmetrical to each other with respect to the central part 76. The angle Q is also substantially equal, in absolute value, to the greatest value envisaged for the adjustment angle s chosen. The greatest value envisaged thus corresponds to the adjustment wedge 50 having the greatest adjustment angle that can be used with the production mold or with other production molds since the same ejection device can be used with the molds. different. Thus, the connecting link 48 can be used with all the adjustment shims 50 envisaged for the production mold. According to one embodiment, the angle Q is also substantially equal to 35 °. The inclined travel surfaces 74 free up a space under the ejection element 28 so as to allow the latter to be oriented according to the adjustment angle s chosen by a rotation with respect to the connecting link 48.

According to one embodiment, the central part 76 itself forms a travel surface substantially parallel to the sliding surfaces 44e, 44f and 44g so that the connecting link 48 has a trapezoid-shaped section rather than a trapezoidal one. triangle on the side of the internal branch 70 opposite to the groove 72. According to one embodiment, the central part 76 however forms a curved surface of radius concentric with the axis carrying the roller 54. Such a curved shape facilitates the rotation of the roller. ejection element 28 relative to connecting link 48, as will now be described.

The connecting link 48 is movable in rotation with respect to the actuating rod 31, for example with respect to a connecting piece 78 integral with the actuating rod 31 and fixed to the latter by a screw 80, as shown in Fig. 4. According to one embodiment, the actuating rod 31, and where appropriate the connecting piece 78, is not in direct contact with the travel surfaces 74 and 76 of the connecting link 48 in order to limit friction. between the ejection rod 31 and the connecting link 48. The connecting link 48 can be oriented relative to the ejection rod 31, the displacement surfaces 74 allowing such an orientation as a function of the value of the adjustment angle s as will be described later. Thus, the connecting link 48 makes it possible to ensure the transition between the transmission chain 40 and the actuating rod 31 whatever the value of the angle of adjustment s in order to ensure a movement along the second axis A2 of the actuating rod 31 whatever this value.

The connection between the connecting link 48 and the connecting piece 78 is for example provided by a connecting element 56 as described above. To this end, the connecting piece 78 and the connecting link 48 comprise at least one pin projecting from the link 48 and from the connecting piece 78, a roller 54 being able to be mounted on these pins, as described above. with reference to the transmission links 42. The rollers 54 also form guide surfaces 52, as also described previously with reference to the transmission links 42.

The ejection device may further comprise one or more ejection rods 82 extending in directions parallel to the first axis A1, as shown in Figs. 1 and 5 to 7. One end of the ejection rod 82 is integral with the ejection plate 16 and its other end is flush with the molding surface 10 in the retracted position of the ejection device and forms a part. of the molding surface 10, as shown in Figs. 1 and 5. The ejection tiger (s) 82 are arranged to allow ejection of the molded article 2 in the direction of opening of the mold, as will now be described.

The operation of the ejection device described above will now be described.

During the molding of the article, the mold is in the closed position and the ejection device is in the retracted position, in which the ejection plate 16 is located in the upstream part 20 of the space 18, the rod d The ejection 82 is flush with the molding surface 10 and in which, according to the embodiment shown in the figures, the ejection element 28 defines with the first part 8 the secondary molding cavity by its secondary molding surface 12.

Once the article has been produced, the mold is opened by separating the first and second mold parts from one another in the opening direction D. During this opening or after it, the ejection device is actuated to move from its retracted position to its ejection position.

To do this, the ejection plate 16 is actuated to move in the space 18 towards the downstream part 22 of this space 18, as shown in FIG. 6. During this movement, the ejection plate 16 moves along the first axis A1 by sliding around the first section 32 of the guide element 33, this first section 32 penetrating into the cavity 38 of the plate d. ejection 16 provided for this purpose. The movement of the ejection plate 16 causes the movement of the ejection rod 82 in a direction parallel to the first axis A1, which moves the molded article 2 away from the molding surface 10 in this direction, as shown in FIG. Fig. 6.

In addition, the movement of the ejection plate causes the movement of the adjustment shim 50 along the first axis A1 which, itself causes the movement of the transmission chain 40 in the guide element 33, the chain of transmission 40 causing the displacement of the ejection element 28.

As shown in Fig. 1, in the retracted position, the transmission links 42 are initially located in the first section 32 of the guide element 33. The movement of the ejection plate 16 causes a movement along the first axis A1 of the links 42 which s' progressively engage in the second section 36 and change direction to move along the second axis A2, as shown in FIG. 6. This change of direction is possible by sliding the sliding surfaces 44 of the links of the transmission chain 40 with respect to each other.

The movement of the links along the second axis A2 causes a movement along this axis of the actuating rod 31 and of the movable block. Due to the angle a between the first axis A1 and the second axis A2, the movement of the actuating rod 31 causes the movable block to slide out of the undercut zone 6, as shown in FIG. 6, which makes it possible to unmold this area. It should be noted that by adapting the value of the adjustment angle o, and therefore of the angle b formed by the sliding surfaces 44, it is possible to delay or accelerate the movement of the movable block out of the undercut zone 6 with respect to the displacement of the pushing device 14. That is to say that, for a displacement at a given speed of the pushing device 14 along the first axis A1, the mobile unit will move at a higher speed , in the case of an accelerated movement, or lower, in the case of a delayed movement, at this given speed. The acceleration or delay of the movement of the movable block relative to the pushing device 14 makes it possible to synchronize the movement of the movable block with that of the ejection rod (s) 82 so that the movable block and the ejection rods 82 reach the ejection position at the same time while the ejection strokes are different.

In Fig. 8, the angle a is substantially equal to 30 ° and the adjustment angle o is zero, that is to say that the adjustment surface 64 of the adjustment shim 50 extends substantially perpendicular to the first axis A1 . In this case, the movable block moves at the same speed as the pushing device 14. In Fig. 9, the angle a is substantially equal to 35 ° and the adjustment angle s is substantially equal to -35 °. In this case, the movable block moves at a speed lower than the speed of movement of the pushing device 14.

In Fig. 10, the angle a is substantially equal to 20 ° and the adjustment angle s is substantially equal to -40 °. In this case, the movable block moves at a speed lower than the speed of movement of the pushing device 14.

In Fig. 11, the angle a is substantially equal to 15 ° and the adjustment angle s is substantially equal to 20 °. In this case, the movable block moves at a speed greater than the speed of movement of the pushing device 14.

In Fig. 12, the angle a is substantially equal to 15 ° and the adjustment angle s is substantially equal to 30 °. In this case, the movable block moves at a speed greater than the speed of movement of the pushing device 14.

Thus, it is understood that by choosing a negative adjustment angle s, the movement of the movable block is delayed and by choosing a positive adjustment angle s, the movement of the movable block is accelerated. The change of adjustment angle is easily done by replacing the adjustment shim 50 with another and possibly also by replacing the connecting link 48, as described above. However, as described above, the same connecting link 48 can be used with the different adjusting shims 50 which can be used in the production mold.

When the ejection plate 16 reaches its ejection position, in which it is for example in contact with the upper wall of the space 18 of the first part 8, as shown in FIG. 7, the molded article 2 is completely separated from the molding surface 10 and the movable block is completely extracted from the undercut area 6. Thus, the molded article 2 can be removed from the mold without hindrance and without interference with the mold. one of the parts of the mold and of the ejection device.

The ejection device described above therefore allows the ejection of molded articles of large dimensions and / or of complex shape without weakening the first part of the mold 8. In addition, the transfer device can be used to adapt the device. ejection to the shape of the molded article 2. The drive chain 40 can be easily changed by adding or removing drive links 42, all of which are identical and interchangeable. In addition, the angle a between the first axis A1 and the second axis A2 can be modified by simply changing an interface piece 84 interposed between the first section 32 and the second section 36. This interface piece 84 also allows or less incline the second section 36 relative to the first section 32. Thus, elements common parts of the ejection device, such as the transmission links 42, the actuating rod 31, the first and second sections 32, 36, the actuating element 24, the ejection plate 16 and the rod (s) ejection 82 can be used for different molds. It suffices to change only the movable block when the shape of the secondary molding surface 12 needs to be changed and / or the interface piece 84 when the angle α needs to be changed and / or the adjustment shim 50 when the angle b must be changed. It will be noted that previously, the angle b was adjusted by modifying the actuating rod 31 so that its interface with the transmission chain imposes the orientation of the desired sliding direction. Thus, to modify the angle b, it was necessary to change the actuating rod 31. According to the invention, the angle b is adjusted by the adjusting wedge 50 and a single actuating rod 31 can thus be used. whatever angle you want. The actuating rod 31 can therefore be machined in a simple manner and have a constant length for different production molds.

The ejection device described above can be modified in various ways while still remaining in accordance with the invention. Thus, by way of example, the ejection element 28 could not include a secondary molding surface and serve only for the separation of the molded article 2 from the molding surface 10, in particular when the main surface 4 of the molded article 2 has areas extending in different directions from a direction substantially perpendicular to the opening direction. The transmission links 42 could also be formed of simple blocks, the outer surfaces of which form the sliding and guiding surfaces. In such an embodiment, the links 42 are not directly linked to each other and are in simple sliding contact with respect to each other.

In addition, it is understood that the mold could comprise several ejection elements 28 and several corresponding transfer devices 26 to allow the molding and the ejection of several undercut zones 6 and / or the ejection of several zones of complex shape. of the main surface 4. In this case, a single ejection plate carrying several adjustment shims 50 can be provided to simultaneously actuate all the ejection elements 28.

Claims

1. Ejection device for a mold producing a molded article (2) in a molding cavity intended to allow the ejection of the molded article (2) out of the molding cavity, said device comprising:

- a thrust device (14) movable in translation along a first axis (A1) between a retracted position and an ejection position,

- at least one ejection element (28) movable in translation along a second axis (A2), different from the first axis (A1), between a retracted position and an ejection position,

- at least one transfer device (26) connecting the pushing device (14) and the ejection element (28), said transfer device (26) being arranged to move the ejection element (28) according to the second axis (A2) between its retracted position and its ejection position when the pushing device (14) is moved along the first axis (A1) between its retracted position and its ejection position, the transfer device (26 ) comprising a transmission chain (40) comprising at least two transmission links (42) movable in translation in a sliding direction with respect to one another and with respect to the pushing device (14) and to the ejection element (28), the ejection device being characterized in that it further comprises at least one adjusting wedge (50) mounted on the pushing device (14), said adjusting wedge (50) comprising an adjustment surface (64) forming an adjustment angle (o) with respect to a direction substantially perpendicular iculaire to the first axis (A1), the transmission chain (40) being mounted on said adjustment surface (64) so that the sliding direction is substantially parallel to said adjustment surface (64).

2. Ejection device according to claim 1, wherein the adjustment angle (o) is negative to delay the movement of the ejection element (28) relative to the pushing device (14), positive to accelerate. moving the ejector member (28) relative to the pusher (14) or zero to move the ejector member (28) at the same speed as the pusher (14).

3. Ejection device according to claim 1 or 2, wherein the transmission chain (40) comprises a connecting link (48), mounted movably in translation on a transmission link (42) on the one hand, the ejection element (28) being mounted movably in rotation on said connecting link (48) about an axis of rotation substantially perpendicular to the first and second axes (A1, A2).

4. Ejection device according to claim 3, wherein the connecting link (48) comprises two travel surfaces (74) of the ejection element (28), the two travel surfaces (74) extending. each from a central portion (76) of the connecting link (48) towards an edge of said connecting link (48), the connecting link (48) being oriented relative to the ejection element (28), the travel surfaces (74) allowing this orientation as a function of the adjustment angle (s) when the ejection element (28) moves along the second axis (A2) between its retracted position and its ejection position .

5. Ejection device according to claim 4, wherein the two travel surfaces (74) of the connecting link (48) are substantially symmetrical to each other with respect to the central part (76) of the link. link (48).

6. Ejection device according to any one of claims 3 to 5, wherein the connecting link (48) is linked to the ejection element (28) by a connecting element (56) articulated to the link. link (48) and to the ejection element (28) so as to allow rotation of the connecting link (48) relative to the ejection element (28).

7. Ejection device according to any one of claims 1 to 6, wherein the transmission chain (40) comprises an adjusting link (46) mounted movably in translation on a transmission link (42), the link adjustment (46) comprising a positioning surface (45) extending over the adjustment surface (64) of the adjustment shim (50) so that the direction of sliding between the adjustment link (46) and the adjustment link transmission (42) is substantially parallel to said adjustment surface (64).

8. An ejection device according to any one of claims 1 to 7, wherein each link of the transmission chain (40) comprises at least two sliding surfaces (44), arranged to slide on sliding surfaces (44). ) adjacent links, said sliding surfaces (44) extending substantially parallel to the adjusting surface (64) of the adjusting shim (50).

9. An ejection device according to any one of claims 1 to 8, wherein each link of the transmission chain (40) is linked to at least one other. link of the transmission chain (40) by at least one connecting element (56) arranged to allow the translational movement of the links with respect to one another.

10. An ejection device according to any one of claims 1 to 9, wherein the transmission links (42) are identical to each other.